Delusion Meaning and Definition in Wikipedia

A delusion is a false belief held by a person. If doctors talk about delusions they mean that the false belief is the result of some disease, usually a disease of the mind, such as paranoia, schizophrenia or bipolar disorder.

Delusions also have other properties, according to Karl Jaspers:

Studies on psychiatric patients show that delusions vary in intensity and conviction over time, which suggests that certainty and incorrigibility are not necessary components of a delusional belief.

Delusions do not necessarily have to be false or 'incorrect inferences about external reality'.

'Delusion' example sentence in quotations

* If we can dispel the delusion that learning about computers should be an activity of fiddling with array indexes and worrying whether X is an integer or a real number, we can begin to focus on programming as a source of ideas. - Harold Abelson

* A human being is part of a whole, called by us the 'Universe,' a part limited in time and space. He experiences himself, his thoughts and feelings, as something separated from the rest--a kind of optical delusion of his consciousness. This delusion is a kind of prison for us, restricting us to our personal desires and to affection for a few persons nearest us. Our task must be to free ourselves from this prison by widening our circles of compassion to embrace all living creatures and the whole of nature in its beauty. - Albert Einstein

* No man is happy without a delusion of some kind. Delusions are as necessary to our happiness as realities. - Christian Nestell Bovee